Wireless communication, such as radio communication, may be arranged to occur between mobile units, such as cellular telephones, wireless-enabled laptops or wireless sensors or other radio-enabled mobile devices, and base stations. A telephone call, for example, may be placed from a smartphone, from where it may be routed via an air interface to a base station. From the base station, the call may be routed through a cellular core network to a call recipient. Alternatively, a smartphone may be arranged to access the Internet, for example, via the air interface to the base station, and from the base station directly to a data communication network whereby a core network is in this case not needed to access the Internet.
Mobile radio-enabled devices, such as suitably enabled cellular telephones, may be capable of communicating with each other directly or locally. Such communication may be known as device-to-device, or D2D, communication.
Direct D2D communication may comprise that a first mobile transmits information encoded in a radio signal, and a second mobile receives the radio signal, wherein the radio signal isn't re-transmitted along the way. In other words, radio energy encoded with information transmitted from the first mobile is received in the second mobile.
Local D2D communication may comprise that a first mobile transmits information encoded in a radio signal, a base station receives the information encoded in the radio signal, and the base station re-transmits the information encoded in a second radio signal, to be received by a second mobile. In local D2D communication, the base station is configured to re-transmit the information to the second mobile without forwarding it to further nodes comprised in a radio-access network or core network.
Communication secrecy is often regulated legally and the right to communication privacy safeguarded. However, in some jurisdictions and subject to judicial oversight, law enforcement officials may have at least partial access to content of communications, such as for example telephone calls and data use. Access to content of communications may be known as lawful interception.
Lawful interception may be implemented in a core network of a cellular communication network, where a node comprised in the core network may be configured to, responsive to operator input, produce copies of communications with a specified terminal as endpoint for use by law enforcement.